Question

A lift is moving downwards with an acceleration equal to due to gravity. If a body of mass $M$ kept on the floor of the lift is pulled horizontally (coefficient of friction $=\mu$), then the frictional resistance offered by the body is

• A. $\mu Mg$
• B. $2\mu Mg$
• C. $Zero$
• D. $Mg$

Answer 1

The correct option is C $Zero$

For downward motion of lift, $R=m(g-a)$
Here, $a=g$
$\therefore R=0$
So, $F=\mu R=0$.